Magneto



July 28, 1936. w J sp 2,048,896

MAGNETO Filed Jan. 16, 1934 INVENTOR BY 40 d. 45 001960 JULY/Less: e/

4 Sheets-Sheet l July 28, 1936.

W. J. SPENGLER MAGNETO Filed Jan. 16, 1934 4 Sheets-Sheet 3 INVENTORSpenger W A TTORNE y July 28, 1936.

W. J. SPENGLER MAGNETO Filed Jan. 16, 1934 4 Sheets-Sheet 4 PatentedJuly 28, 1936 MAGNETO Walter J. Spengler, Sidney, N. Y., assignor, by

mesne assignments, to Bendix Aviation Corporation, South Bend DelawareInd., a corporation of Application January 16, 1934, Serial No. 706,857

15 Claims.

This invention relates to magneto generators and more particularly to ahigh tension generator particularly adapted for the ignition of internalcombustion engines.

It is an. object of the present invention to provide a novel hightension generator which is simple and rugged in construction andefficient and reliable in operation.

It is another object to provide such a device which incorporates animpulse coupling formed as a unit therewith.

It is a further object to provide such a device in which the variousmoving parts are readily assembled and the bearings therefor are soarranged as to provide a rigid assembly free from end play or lostmotion.

' It is another object to provide such a device which may be easilytaken down, adjusted and reassembled without the use of special tools.

Further objects and advantages will be apparent from the followingdescription taken in connection with the accompanying drawings in which:

Fig. 1 is .a view in perspective of a magneto generator embodying apreferred form of the present invention;

Fig. 2 is substantially a vertical axial section of the device;

Fig. 3 is a top top cover plate removed;

Fig. 4 is a perspective view partly in section of the drive shaft andits associated parts;

Fig. 5 is a perspective view of the rotor and its associated parts,partially disassembled;

Fig. 6 is a perspective view of the driving shaft and rotor in assembledrelation;

Fig. 7 is a vertical section taken substantially on theline 1-1 of Fig.3;

Fig. 8 is a vertical section taken substantially on the line 8-8 of Fig.2;

Fig. 9 is a vertical section taken substantially on the line 9-9 of Fig.2; and

plan view of the device with the Fig. 10 is a view similar to Fig. 9showing the I parts of the impulse coupling in active position.

Referring first to Figs. 1, 2 and 3 of the drawlngs, there isillustrated an integral frame member I generally in the shape of arectangular box having one open end which is arranged to be closed by anend cover plate 2 detachably fixed thereto as by means of studs 3, andan opening in the top adapted to be closed by a top cover member 4detachably fixed to the frame 5. The closed end of the frame I isprovided with a bearing seat 6, and the end cover plate 2 is alsoprovided with a bearing seat I in alignment therewith.

by means of studs A driving shaft 8 (Figs. 2 and 4) is provided with asmooth surface of relatively-large diameter adapted to receive a hearingI I which is arranged to fit the seat I in the end plate 2. The bearingI I is adapted to be retained in end plate 2 by suitable means such as athrust ring and grease retaining member ID which is held in position byswedging over the edge of the seat 'I in the end plate. Adjacent theportion 9 of the drive shaft, the shaft is reduced in diameter asindicated at I2, forming a shoulder I3. Toward the inner end of theshaft 8 a third smooth portion I4 of further reduced diameter isprovided, and the portion I5 of the shaft between the parts I2 and I4 isstill further reduced to provide a clearance space. The inner end ofshaft 8 is provided with a bearing seat I6 of a diameter slightlysmaller than the portion I4, on which a bearing I1 is arranged to beheld by suitable means such as a locking ring I8 engaging in a groove I9at the end of the shaft. Preferably a thrust ring and grease retainingelement 2| is inserted between the bearing I1 and the shoulder 22 formedbetween the portions I4 and I6 of the shaft.

A rotor indicated generally by numeral 23 (Figs. 2 and 5) is freelyjournalled-on the driving shaft 8 by means of the bearing portions I2and I4 of said I shaft. The rotor 23 comprises a central hollow sleeve24 formed at one end as at 25 to bear on the portion I2 of the shaft,and having a portion 26of reduced internal diameter for bearing on theportion l4 of the shaft. 'A magnetic end plate 21 is fixedly mounted inany suitable way on the end 25 of the sleeve 24, being positionedthereon preferably by means of interengaging shoulders 28 therebetween.A non-magnetic end plate 29 is mounted on the 'end 26 of sleeve 24 andis suitably fixed thereto as by means of-a groove 3| in the sleeve intowhich a lip 32 of the end plate 29 is forced when the'parts areassembled.

A plurality of bar magnets 33 of equal length are disposed axiallyabout'the sleeve 24 between the end plates 21 and 29, being clampedtightly between said plates when the end plate 29 is assembled to thesleeve 24. As here shown, these bar magnets are four in number and arearranged in groups of two having their poles similarly disposed, the twogroups having their poles oppositely disposed. The poles of each groupof magnets adjacent the non-magnetic end plate 29 are united by means ofpole pieces 34 of magnetic material, which are preferably formed asshown of laminations of pure iron. All the magnet bars are united bymeans of lamination's of non-magnetic material such as aluminum orbrass, sufiicient laminations being used to comrim of the end plate 21.

pletely fill the space between the end plates 21 and 28 whereby when theend plate 28 is forced into position on the sleeve 24, all the parts ofthe rotor aretightly clamped together into a rigid unit. The laminations85 of the rotor are further clamped together by means of bolts 36traversing the magnetic end plate 21 and provided with nuts 31 which maybe tightened by means of a screw driver, openings 88 being provided [inthe non-magnetic end plate 28 for that purpose.

The rotor 23 is yieldably connected to the driving shaft 8 by resilientmeans in the form of a coiled spring 38 seated in the clearance spaceformed by the portion l5 of the shaft 8 and'anchored to said shaft atone end as by means of a terminal portion 4| traversing an opening inthe shaft. The opposite end 42 of the spring is bent axially and extendsinto a slot 43 in the magnetic end plate 21, suitable slots 44 and 45being provided in the sleeve 24 and laminations 35 to permit theassembly of the shaft and spring within the rotor. This resilientconnection between the shaft and rotor forms one element of an impulsecoupling whereby at low speeds of the driving shaft the rotor isretarded and accelerated periodically in order to generate adequateignition current at the proper intervals.

In order to provide the retarding means of the impulse coupling, themagnetic end plate 21 is formed with a cup-like recess 46, and acentrifugal weight or latch member 41 (Figs. 9 and 10) is pivoted at 48on the head of one of the bolts 36. The point 49 of the latch is adaptedto project beyond the periphery of the cup 46 and engage a stop memberin the form ofa stud 5| in the magneto frame, thereby obstructing therotation of the rotor. Means are provided for tripping the latch-in theform of a stud 52 mounted on a flanged control member 53 which isrigidly fixed on the shaft 8 against the shoulder I3. The control member58 is preferably rigidly attached to the shaft 8 by means of a knurledgroove 54 formed in the smooth portion l2 of the shaft, a lip 55 of saidcontrol member being forced into said groove to make intimate contacttherewith. It will be noted that the endsurface 56 of the control memberprovides a thrust bearing for the sleeve 24 of the rotor, cooperatingwith the thrust ring 2 to define the longitudinal position of the rotoron the shaft. By reference to Figs. 4 and. 6 of the drawings, it will benoted that a plurality of threaded openings 58 for the stud 52 areprovided in the control member 58 in order that the amount of wind-up ofthe spring 88 prior to the tripping of the centrifugal weight 41 may besuitably predetermined.

The control member 58 is provided with radially extending lugs 54 whichare arranged to engage abutments 55 extending axially from the Theengagement of the lugs 54 against the abutments 55 under the action ofthe spring as shown in Fig. Q'defines the normal rotary position of therotor on the shaft. The, latch 41 is provided as shown with a weightedportion 51 which causes the engagement of the latch with the stop 5| atlow speed as indicated in Fig. 10, but which causes the latch to bewithdrawn by centrifugal force as 'soon as the rotor attains a properoperative speed. The frame I is provided with stationary magnetic polepieces 58 and 58 (Fig. 8) preferably formed integrally therewithas by acasting process. These pole pieces are arranged to closely surround thepole pieces 84 of the rotor, and extend upwardly above the frame asindicated at 6| and 62. A coil assembly 68 having the usual primary andsecondarywindings and'a magnetic core 64 is mounted'between the upwardlyextending portions 6|, 62 of the stationary pole pieces, the core 64being suitably fixed to said pole pieces at its ends as by meansterminal 68 is held in place by a knurled mit 68a, the tightening ofwhich compresses a soft rubber bushing 68b around the ignition cable soas to seal it against dirt and moisture. The terminal 68 is carried inthe top cover plate 4 which is arranged to surround the coil 68 andcompletely close and seal the top opening of the frame I.

The insulated end of the primary winding of coil- 68 is connected bymeans of a lead 18 to a breaker mechanism mounted the closed end of theframe I. As shown more particularly in Figs. 2 and 7 of the drawings,this breaker mechanism comprises a cam 14 suitably keyed as indicated at15 on the end of the rotor sleeve 24, and a follower 16 mounted on aspring 11 in position to engage a second spring element 18 carrying atits end a movable contact 18. The springs 11 and 18 are fixed asindicated at 8| to a bracket 82 which is detachably mounted in the frameI by means of a cap screw 83. Lubricating means for the cam follower 16are preferably provided in the form of an oil saturated wick 84. e

A stationary contact 85 is carried by a bracket 86 in juxtaposition tothe movable contact 18, the bracket 86 being carried by an insulatedterminal member -81 extending out through the frame I. Terminal member81 is fixed to the frame as by means of a nut 88, and serves as abinding post for a grounding lead adapted to be connected thereto bymeans of a nut 88. The bracket 86 is adjustably fixed to the terminalmember 81 by means of a cap screw 8|.

The cap screw 8| serves further as a unitary means for attaching theprimary lead 18 to the terminal member 81, and also for attachingthereto a condenser lead in the form of a spring strip 82 which'isflxedas indicated at 88 to thei cap screw 8|.

In assembling the magneto structure, the shaft 8 with the control member68 and the spring 88 thereon is slid within the rotor 28 until the endof. the sleeve 24 engages the thrust surface 56 of the controlmember 58,and the lugs 54 of the control member come into operative 75 relationwith the abutments 55 of the end plate 21. The thrust ring 2i andbearing H are then slid on the portion l6 of the shaft and retainedthereon by the locking member l8. End cover plate 2 with the bearing llseated therein is then placed on the portion 9 of the shaft, and acoupling member 98 of conventional form is fixed to the shaft asindicated at 99.

The shaft and rotor assembly is now inserted in the open end of theframe I until the hearing I! engages the seat 6 of the frame and the endcover plate 2 closes the end opening of the frame where it is retainedby the studs 3. The breaker mechanism and condenser are then placed inposition, the coil 63 mounted, the lead 13 is connected up andtheb'reaker points adjusted and locked in position by tightening the capscrews 83 and 9|. The top cover plate 4 is then placed in position andanchored'by studs 5.'

It will be noted that the magneto here illustrated is of the left-handdrive type; that is, the rotor turns counter-clockwise when viewed fromthe driving end. To convert the machine to right-hand drive, it ismerely necessary to change the centrifugal weight 41 over to theother-bolt 48, move the stop member 5| to the other side of the frame Iin place of the dummy member 5|, exchange the spring 39 for a right-handtype, and reset the breaker cam 14 on sleeve 24, an opposite keyway I5being provided for righthand rotation. The rest, of the breakermechanism is designed to operate in either direction of rotation.

In the operation of this device, slow rotation of the shaft 8 from theengine through-the coupling 98 as during the -cranking operation, causesthe rotor 23 to turn therewith until the latch 41 engages the stop 5| asshown in Fig. 10. Further rotation of the shaft causes the spring 39 tobe wound up until the stud 52 engages the end 51 of the latch and tripsthe same. Thereupon the rotor quickly accelerates until the lugs 54 ofthe control member engage the abutments 55 of the end plate 21. It willbe understood that this period of rapid rotation of the rotor isso timedV as to occur in proper relation with the functioning of the engine, andthat the breaker points 19 and 85 are timed to open at the proper,instant to obtain the spark at the correct time. As soon as the'enginebecomes self-operative, the speed of the magneto causes the weight 41 tobe moved into its inoperative position by centrifugal force, after whichthe rotor and shaft rotate as a unit.

It will be seen that there is here provided a magneto in which animpulse coupling is incorporated as an integral part of the magnetoitself, and the bearings of the various rotating parts are sodimensioned and spaced axially as to secure an extremely rigidconstruction. It will further be noted that the device may be taken downand assembled without the use of special tools, and that the parts ofthe breaker mechanism are exposed for easy adjustment upon the removalof the top cover 4.

Although one embodiment of the invention has been shown and described indetail, it will be understood that other embodiments are possible andthat changes may be made in the design and arrangements of the partswithout departing from the spirit of the invention as defined in theclaims appended hereto.

What is claimed is: 1. In a magneto a frame having spaced bearingstherein, a driving shaft mounted in said bearings, a rotor looselymounted on said shaft between said bearings, and an impulse couplingwithin said rotor connecting said shaft and rotor.

2. In a magneto a frame having spaced bearings therein, a driving shaftmounted in said bearings, a rotor loosely mounted on said shaft betweensaid bearings, resilient means within the rotor for driving the rotorfrom the shaft, means for periodically obstructing the rotation of therotor, and means for periodically releasing the rotor and permitting itto be rapidly accelerated into rotation with the drive shaft.

3. In a magneto a frame having spaced bearings therein, a driving shaftmounted in said bearings, a rotor loosely mounted on said-shaft,

between said bearings, and bearing at its ends on said shaft, a coiledspring mounted on the shaft Within the rotor and connected at its endsto the shaft and rotor respectively means on the rotor and frame adaptedto engage periodically and obstruct the rotation of the rotor, and meanson said shaft adapted to disengage said obstructing means after apredetermined winding-up of said spring.

4. A magneto generator having a frame of generally rectangular outline,bearings mounted in the ends of said frame, a drive shaft mounted insaid bearings, a rotor journalled on said shaft between" said bearings,cooperating means on the shaft and rotor adapted to engage and limitadvance rotation of the rotor on the shaft, resilient means on the shaftnormally maintaining the rotor in a fixed position thereon, cooperatingmeans on the rotor and frame for periodically erally rectangularoutline, bearings mounted in the ends of said frame, a drive shaftmounted in' said bearings, a rotor journalled on said shaft between saidbearings, a control element fixed to said shaft adjacent the rotor, anabutment on said a rotor adapted to engage said control element,yielding means urging said abutment into such engagement, a stop on theframe, a latch on the rotor adapted to engage said stop, and a trip on'said control element arranged to disengage said latch,

6. A magneto comprising a frame having an integral body portion with abearing seat at one end-and an end plate having a second bearing seat, adriving shaft, a rotor journalled thereon, a resilient coupling betweenthe shaft and rotor, bearings on the said shaft adapted to fit saidbearing seats, and means for retaining said bearings on the shaftwhereby, end plate, the shaft, rotor, coupling and bearings areremovable from the frame as a unit.

7. A magneto comprising a, frame having an integral body portion with abearing seat at one end and an end plate having a second bearing seataligned with said first seat, a stator fixed upon removal of the in theframe between said bearing seats, a straight rigid driving shaft, arotor journalled thereon, a resilent coupling between the shaft androtor, bearings on said shaft adapted to fit said bearing seats, andmeans for retaining said bearings on the shaft whereby, upon removal ofthe end plate,

. the shaft, rotor coupling and bearings are removable from the frame asa unit, said shaft, when the 8. In a magneto, a rotor comprising a.hollow 'parts are assembled, serving to maintain the parts non-magneticsleeve having a shoulder at one end, a magnetic end plate seated againstsaid shoulder, a non-magnetic end plate fixed to said sleeve adjacentits opposite end, a plurality; of bar magnets spaced circumferentiallyabout said sleeve between said end plates, magnetic pole pieces mountedon the poles of the magnets adjacent the non-magnetic end plate.non-magnetic means for uniting the remaining portions of the magnetswith the sleeve, a driving shaft journailed within said sleeve andcoupling means for rotating said sleeve from the driving shaft.

9. In a magneto, a rotor comprising a hollow non-magnetic sleeve havinga shoulder at one end, a magnetic end plate seated against. saidshoulder, a non-magnetic end plate fixed to said sleeve adjacent itsopposite end, a plurality of axially arranged bar magnets spacedcircumferentially in groups having their poles in alternation about saidsleeve between said end plates, magnetic pole pieces uniting each groupof poles of the magnets adjacent the non-magnetic end plate,non-magnetic means for uniting the remaining portions of all the magnetswith the sleeve, a driving shaft journalled within said sleeve, andcoupling means for rotating said sleeve from the driving shaft.

10. In a magneto, a rotor comprising a hollow non-magnetic sleeve, anend plate fixed thereon formed to-provide a cup, a latch carried in saidcup, a driving shaft journalled in said sleeve having a flange memberrigid therewith forming a closure for said cup, resilient meansconnected respectively to the sleeve and shaft for driving the rotorfrom the shaft, and means on said flange member for tripping said latchafter a predetermined fiexure of the driving means.

11. In a magneto, a rotor comprising a hollow non-magnetic sleeve, anendplate fixed thereon formed to provide a cup, a centrifugal latch carriedin said cup, a driving shaft journalled in said sleeve having a flangemember rigid therewith forming a closure for said cup, aspring withinsaid sleeve anchored at its ends to the sleeve and shaft respectively,and means on said flange member for tripping said latch after apredetermined fiexure of the spring.

12. A magneto comprising an integral frame in the form of a box open atthe top and at one aoaaaee end a rotonand breaker cam assembly and anend plate insertable as a unit in the open end of the 'frame,.'a;coilunit mounted on the top of the frame, breaker mechanism insertablethrough the ,top of the frame and detachably mounted in position tocooperate with said cam, and a cover plate and high tension terminaldetachably mounted on the top of the frame.

13. A magneto comprising an integral frame in the form of a box open atthe top and at one end, and containing stationary pole pieces, a rotorand breaker cam assembly and an end plate insertable as a unit in theopen end of the frame, said rotor having magnetic elements arranged tocooperate with said pole pieces, a coil unit mounted on the top of theframe having a core in magnetic circuit with said pole pieces, breakermechanism insertable through the top of the frame and detachably mountedin position to cooperate with said cam, and a cover plate and hightension terminal detachably mounted on the top of the frame, surroundingsaid coil and closing the frame.

14. In a magneto an integral frame in the form of a box open at the topand at one end, a drive shaft, rotor and breaker cam assembly and an endcover plate insertable as a unit in the open end of the frame, acondenser and breaker mechanism insertable and adjustable through thetop of the frame, and unitary means readily operable through the top ofthe frame serving to hold the condenser in place and to maintain theadjustment of the breaker mechanism.

15. In a magneto an integral frame in the form of a box open at the topand at one end, a drive shaft, rotor and breaker cam assembly and an endcover plate insertable as a unit in the open end of the frame, a statorincluding a coil assembly fixed on the frame, a condenser and breakermechanism insertable and adjustable through the top of the frame, a lowtension lead from the coil to the breaker mechanism, and unitary meansreadily operable through the top of the frame for holding the condenserin, place, maintaining the adjustment of the breaker mechanism, andserving as a binding post for said low tension lead.

WALTER J. SPENGLER.

